Auction # 2506 WORLDWIDE + ARGENTINA: Special auction Punta del Este Exposition

BRITISH POSTAL AGENCY IN BUENOS AIRES: Cover sent collect from Buenos Aires to Olten (Switzerland) on 30/MAR/1861 by British mail. On back it bears a datestamp of the Consular Agency, London transit mark, Swiss Basel-Olten traveling PO cancel, and arrival mark of 6/MAY, and on front several due marks applied on transit, and a French-British exchange datestamp, excellent quality!